I have a file (file_name) which contains exactly one occurance of the string Result:, at the start of a line. I want to print all the characters after the string Result: in that line until I encounter a space. Which shell command should I use?

There is a blank behind the colon : and afaik, the word before the next colon is searched.
– user unknownNov 7 '11 at 4:39

the OP doesn't mention a second colon. Just that the string ocurring between Result: and the next space are what is desired. Awk will by default break up the line on white space. $1 = "Result:", $2 = the next word. Which is what the OP requested to extract.
– Tim KennedyNov 7 '11 at 5:10

Sorry - I meant 'before the next blank'. Your command results for the line Result:two bla nk in bla.
– user unknownNov 7 '11 at 5:29

I have updated my example to specifically include the space after the colon following Result: . This will now ignore lines like that in your example, and more closely match the initial request of the OP.
– Tim KennedyNov 7 '11 at 5:40